1. Field of the Invention
The present invention relates to an inking device equipped with an ink fountain device which allows ink in an ink fountain to flow out continually in a predetermined amount.
2. Description of the Related Art
An inking device supplies printing ink to a plate mounted on a plate cylinder of a web offset printing press or the like. The inking device is composed of an ink fountain device for allowing ink, stored in an ink fountain, to flow out in a predetermined amount at a time, and a group of many rollers for guiding the ink, which has flowed out, to a plate surface while leveling off the ink in different directions.
In recent years, special inks, such as optical variable ink (OVI), have come into use for prevention of forgery particularly in the field of printing of various securities. Generally, special inks are so expensive that they are often applied to small patterns. With an ink fountain device of a width adapted for a conventional paper size (see Japanese Patent Publication No. 54197/89, the amount of ink fed was large. Once fed, the ink could not be reused. Thus, the cost was high compared with the area of printing.
Japanese Utility Model Publication No. 46675/94, for example, discloses an ink fountain device for resolving the above-mentioned drawback. As shown in FIG. 11, an elongated holder 102 is detachably fixed to an upper surface of an ink fountain support member 101 provided beside an ink fountain roller 100. To the holder 102, a blade 103 formed of a steel sheet is secured such that a front end of the blade 103 is nearly in contact with a circumferential surface of the ink fountain roller 100. To the holder 102, a pair of side plates 105 are also fixed via support fittings 104. The side plates 105 are formed in a nearly inverted triangular shape, have side surfaces pressed against both edges of the blade 103, and have front end arcuate surfaces pressed against the circumferential surface at both ends of the ink fountain roller 100. The side plates 105, the circumferential surface of the ink fountain roller 100, and the blade 103 define a gutter-shaped ink fountain 106. Between the right and left side plates 105, a holder shaft 107 parallel to the ink fountain roller 100 is supported on the ink fountain support member 101 via brackets 108 in proximity to a rear end of the holder 102 for the blade. On the holder shaft 107, a plurality of (three in the drawing) divisional interceptor devices 109 are arranged parallel to each other so as to be movable and adjustable in an axial direction of the holder shaft 107.
According to the foregoing ink fountain device, two of the divisional interceptor devices 109 are moved on the holder shaft 107 until they are each located at a boundary position between a pattern-corresponding area and a non-pattern-corresponding area. Then, a predetermined ink is put between these divisional interceptor devices 109. By so doing, ink can be supplied to the pattern-corresponding area only, so that the consumption of ink can be decreased.
With the above-described conventional ink fountain device, however, a plurality of adjusting screws (not shown) for adjusting a clearance between the circumferential surface of the ink fountain roller 100 and the front end of the blade 103 are located at fixed positions. Even when the divisional interceptor devices 109 are moved in agreement with the pattern, therefore, the positions of the adjusting screws may fail to fully correspond with the pattern. As a result, the clearance is adjusted incompletely, thereby making it impossible to adjust the amount of ink supply accurately and finely in the direction of paper width.